The letter addresses four key elements the organization wants Facebook and other internet sites to address: tell the truth, ban the bots, alert the public and fund the fact-checkers.

“We want Facebook to tell the truth regarding the work that is being done to stop this and the scale of the fake news and fake post problem. We just want to know the transparency of the problem and what is being done to tackle it,” Greenberg said.

The group says the cutouts represents the hundreds of millions of fake accounts still spreading disinformation on Facebook.

Each is wearing a shirt that reads “Fix Fakebook.”

This is the first time Zuckerberg will personally sit for questions from Congress. His testimony marks a pivotal moment for Facebook, as Zuckerberg will spend two days answering lawmakers’ questions about what the company is doing to protect users’ privacy.